Treatment of class 2 division 1 malocclusion with severe short roots of upper central incisors

摘要

The average amount of resorption per root of examined maxillary incisors or anterior teeth is < 1.5 mm during comprehensive orthodontic treatment. About 5% of adults and 2% of adolescents are likely to have at least one tooth with resorption of more than 5 mm during active treatment. Although resorption stops once the active appliances are removed, fortunately, truly severe resorption that threatens the longevity of the tooth or forces a halt to treatment is rare. The fact is, however that orthodontic tooth movement does directly cause irreversible resorption of the root. As the movers of the teeth, it is incumbent for us to know as much as possible about the causes, effects and prevention of this phenomenon.KEY WORDS: Frankel appliance, fixed appliance, short roots